Dan Pfeiffer, the White House communications director, said the “recess appointment” was needed to carry out the new health care law, which calls for huge changes in the two programs, which together insure nearly one-third of all Americans.

Mr. Pfeiffer said the president would appoint Dr. Berwick on Wednesday. Mr. Obama decided to act because “many Republicans in Congress have made it clear in recent weeks that they were going to stall the nomination as long as they could, solely to score political points,” Mr. Pfeiffer said.

As a recess appointee, Dr. Berwick will have all the powers of a permanent appointee. But under the Constitution, his appointment will expire at the end of the next session of Congress, in late 2011.

In April, Mr. Obama nominated Dr. Berwick to be administrator of the Centers for Medicare and Medicaid Services. The agency has been without a permanent administrator since October 2006.

The recess appointment was somewhat unusual because the Senate is in recess for less than two weeks and senators were still waiting for Dr. Berwick to submit responses to some of their requests for information. No confirmation hearing has been held or scheduled.

President Obama drew criticism on Thursday when he said, “we don’t have a strategy yet,” for military action against ISIS in Syria. Lawmakers will weigh in on Mr. Obama’s comments on the Sunday shows.Read more…